Image sensor

ABSTRACT

An image sensor is provided. The image sensor includes: a pixel array including first and second pixel groups, each of which includes unit pixels arranged in 4×4 array, each of the unit pixels including a photodiode provided, and the first and second pixel groups being alternately disposed in multiple directions; a logic circuit configured to acquire pixel signals from the unit pixels; first microlenses provided on corresponding unit pixels in the first pixel groups; and second microlenses provided on four corresponding unit pixels of the unit pixels included in the second pixel groups. Each of the first and second pixel groups includes a device isolation layer provided between the unit pixels, and a color filter provided on the first surface, and each of the second pixel groups includes an overflow region configured to move electrical charges between adjacent photodiodes.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to Korean Patent Application No.10-2021-0051595 filed on Apr. 21, 2021 in the Korean IntellectualProperty Office, the disclosure of which is incorporated by referenceherein in its entirety.

BACKGROUND

Methods, apparatuses and systems consistent with example embodimentsrelate to an image sensor.

Image sensors may be semiconductor-based devices that generateelectrical signals upon receiving light, may include a pixel arrayincluding a plurality of unit pixels and a circuit for driving the pixelarray and generating an image. Each of the plurality of unit pixels mayinclude a photodiode which generates an electrical charge in response toexternal light that is incident thereon, and a pixel circuit whichconverts the electrical charge generated by the photodiode into anelectric signal. The image sensor may be widely applied to smartphones,tablet PCs, laptop computers, televisions, automobiles, and the like, inaddition to cameras for capturing images or video. Recently, research toimprove autofocusing performance along with research to createhigh-quality images, has been conducted.

SUMMARY

One or more example embodiments provide an improved image sensor forsecuring autofocusing with respect to four directions, preventingsaturation of electrical charges generated by a photodiode, andgenerating a high-quality image.

According to an aspect of an example embodiment, an image sensorincludes: a substrate having a first surface and a second surface whichfaces the first surface; a pixel array including a plurality of firstpixel groups and a plurality of second pixel groups, each of theplurality of first pixel groups and each of the plurality of secondpixel groups including a plurality of unit pixels arranged in 4×4 arraythat extends in a second direction and in a third direction, each of theplurality of unit pixels including a photodiode provided in thesubstrate, and the plurality of first pixel groups and the plurality ofsecond pixel groups being alternately disposed in the second directionand in the third direction; a logic circuit configured to acquire pixelsignals from the plurality of unit pixels; a plurality of firstmicrolenses, each of which is provided on a corresponding unit pixel ofthe plurality of unit pixels included in the plurality of first pixelgroups; and a plurality of second microlenses, each of which isrespectively provided on four corresponding unit pixels of the pluralityof unit pixels included in the plurality of second pixel groups that arearranged in a 2×2 array. A first direction is perpendicular to the firstsurface of the substrate, the second direction is parallel to the firstsurface of the substrate, and the third direction is parallel to thefirst surface of the substrate and perpendicular to the seconddirection. Each of the plurality of first pixel groups and each of theplurality of second pixel groups includes a device isolation layerprovided between the plurality of unit pixels, and a color filterprovided on the first surface, and each of the plurality of second pixelgroups includes an overflow region configured to move electrical chargesbetween adjacent photodiodes.

According to an aspect of an example embodiment, an image sensorincludes: a substrate having a first surface and a second surface whichfaces the first surface; a pixel array including a plurality of subpixelgroups including a plurality of first subpixel groups and a plurality ofsecond subpixel groups, each of the plurality of first subpixel groupsand each of the plurality of second subpixel groups including aplurality of unit pixels arranged in a 2×2 array that extends in asecond direction and in a third direction, and a floating diffusionregion that is shared by the plurality of unit pixels arranged in the2×2 array, and each of the plurality of unit pixels including aphotodiode provided in the substrate; a logic circuit configured toacquire pixel signals from the plurality of unit pixels; a plurality offirst microlenses, each of which is provided on a corresponding unitpixel of the plurality of unit pixels included in the plurality of firstsubpixel groups; and a plurality of second microlenses, each of which isrespectively provided on a plurality of corresponding unit pixels of theplurality of second subpixel groups. A first direction is perpendicularto the first surface of the substrate, the second direction is parallelto the first surface of the substrate, and the third direction isparallel to the first surface of the substrate and perpendicular to thesecond direction. Each of the plurality of subpixel groups is adjacentto one of the plurality of first subpixel groups and one of theplurality of second subpixel groups in each of the second direction andthe third direction, and includes a device isolation layer providedbetween the plurality of unit pixels and separated from the floatingdiffusion region in the second direction and in the third direction, andadjacent portions of the device isolation layer extending in the seconddirection in the plurality of first subpixel groups are closer to eachother than adjacent portions of the device isolation layer extending inthe second direction in the plurality of second subpixel groups.

According to an aspect of an example embodiment, an image sensorincludes: a substrate having a first surface and a second surface whichfaces the first surface; a pixel array including a plurality of firstpixel groups and a plurality of second pixel groups, each of theplurality of first pixel groups and the plurality of second pixel groupsincluding a plurality of unit pixels defined by a device isolation layerextending through the substrate in a first direction, the plurality ofunit pixels in each of the plurality of first pixel groups and theplurality of second pixel groups being arranged in 4×4 array thatextends in a second direction and in a third direction, each of theplurality of unit pixels including a photodiode provided inside thesubstrate, and the plurality of first pixel groups and the plurality ofsecond pixel groups being alternately disposed in the second directionand in the third direction; a logic circuit configured to acquire pixelsignals from the plurality of unit pixels; a plurality of firstmicrolenses having a first diameter and respectively corresponding tothe plurality of unit pixels are disposed on an upper surface of theplurality of first pixel groups; and a plurality of second microlenseshaving a second diameter greater than the first diameter are disposed onan upper surface of the plurality of second pixel groups. The firstdirection is perpendicular to the first surface of the substrate, thesecond direction is parallel to the first surface of the substrate, andthe third direction is parallel to the first surface of the substrateand perpendicular to the second direction, and a pixel signal acquiredfrom unit pixels of the plurality of unit pixels sharing one of theplurality of second microlenses includes an autofocusing pixel signalwith respect to the second direction and the third direction.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages will be moreclearly understood from the following detailed description, taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating an image sensor according to anexample embodiment;

FIG. 2 is a circuit diagram illustrating a pixel circuit of an imagesensor according to an example embodiment;

FIGS. 3 and 4 are plan views illustrating a pixel array included in animage sensor;

FIG. 5 is a plan view illustrating pixel groups included in an imagesensor according to an example embodiment;

FIG. 6 is a plan view illustrating a first pixel group included in animage sensor according to an example embodiment;

FIGS. 7 to 9 are cross-sectional views illustrating the first pixelgroup included in an image sensor according to an example embodiment;

FIG. 10 is a plan view illustrating a second pixel group included in animage sensor according to an example embodiment;

FIGS. 11 to 13 are cross-sectional views illustrating the second pixelgroup included in an image sensor according to an example embodiment;

FIGS. 14A, 14B, 15A, 15B, 16A, 16B and 17 are views illustrating aprocess of manufacturing an image sensor according to an exampleembodiment;

FIGS. 18 to 20 are plan views illustrating pixel groups included in animage sensor according to another example embodiment;

FIGS. 21 to 24 are plan views illustrating pixel arrays included in animage sensor according to example embodiments; and

FIGS. 25 and 26 are views illustrating an electronic device including animage sensor according to an example embodiment.

DETAILED DESCRIPTION

Hereinafter, example embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a block diagram illustrating an image sensor according to anexample embodiment.

Referring to FIG. 1, an image sensor 1 according to an exampleembodiment may include a pixel array 10 and a logic circuit 20.

The pixel array 10 may include a plurality of unit pixels PX arranged ina plurality of rows and a plurality of columns Each of the unit pixelsPX may include at least one photoelectric conversion element whichgenerates an electrical charge in response to light that is incidentthereon, and a pixel circuit which generates a pixel signalcorresponding to the electrical charge generated by the photoelectricconversion element.

The photoelectric conversion device may include a photodiode formed of asemiconductor material and/or an organic photodiode formed of an organicmaterial. In an example embodiment, each of the unit pixels PX mayinclude two or more photoelectric conversion elements, and the two ormore photoelectric conversion elements included in one unit pixel PX mayreceive light of different colors and generate electrical charges. In anexample embodiment, each of the plurality of unit pixels PX may includea photodiode which generates an electrical charge upon receiving light.However, this is an example and example embodiments are not limitedthereto.

According to an example embodiment, the pixel circuit may include atransfer transistor, a driving transistor, a select transistor, and areset transistor. When each of the unit pixels PX includes onephotoelectric conversion element, each of the unit pixels PX may includea pixel circuit for processing electrical charges generated by thephotoelectric conversion element. For example, each of the plurality ofunit pixels PX included in the image sensor 1 according to an exampleembodiment may include a photodiode. Accordingly, a pixel circuitcorresponding to each of the unit pixels PX may include a transfertransistor, a driving transistor, a select transistor, and a resettransistor.

However, this is only an example and embodiments are not limitedthereto. For example, the plurality of unit pixels PX included in theimage sensor 1 according to an example embodiment may share a floatingdiffusion region in units of subpixel groups, and accordingly, at leastsome of the photoelectric conversion elements may share some of thedrive transistor, the select transistor, and the reset transistor.

The logic circuit 20 may include circuits for controlling the pixelarray 10. For example, the logic circuit 20 may include a row driver 21,a read-out circuit 22, a column driver 23, and a control logic 24.

The row driver 21 may drive the pixel array 10 in a row unit. Forexample, the row driver 21 may generate a transfer control signal forcontrolling the transfer transistor of the pixel circuit, a resetcontrol signal for controlling the reset transistor, a select controlsignal for controlling the select transistor, and the like and input thegenerated signals to the pixel array 10 in units of rows.

The read-out circuit 22 may include a correlated double sampler (CDS),an analog-to-digital converter (ADC), and the like. The CDSs may beconnected to the unit pixels PX through column lines. The CDSs mayperform correlated double sampling by receiving pixel signals from unitpixels PX connected to a row line selected by a row line select signalfrom the row driver 21. The pixel signals may be received via the columnlines. The ADC may convert the pixel signal detected by the CDS into adigital pixel signal and transmit the digital pixel signal to the columndriver 23.

The column driver 23 may include a latch or buffer circuit fortemporarily storing a digital pixel signal, an amplifier circuit, andthe like, and may process a digital pixel signal received from theread-out circuit 22. The row driver 21, the read-out circuit 22, and thecolumn driver 23 may be controlled by the control logic 24. The controllogic 24 may include a timing controller for controlling an operationtiming of the row driver 21, the read-out circuit 22, and the columndriver 23.

Among the unit pixels PX, the unit pixels PX arranged at the sameposition in the horizontal direction may share the same column line. Forexample, unit pixels PX arranged at the same position in the verticaldirection may be simultaneously selected by the row driver 21 and mayoutput pixel signals through column lines. In an example embodiment, theread-out circuit 22 may simultaneously acquire pixel signals from theunit pixels PX selected by the row driver 21 through column lines. Thepixel signal may include a reset voltage and a pixel voltage, and thepixel voltage may be a voltage in which an electrical charge generatedin response to light in each of the unit pixels PX is reflected in thereset voltage. However, example embodiments are not limited to thecomponents described above with reference to FIG. 1, and the imagesensor may additionally include other components and may be driven invarious manners.

FIG. 2 is a circuit diagram illustrating a pixel circuit of an imagesensor according to an example embodiment.

A plurality of unit pixels PX included in the image sensor 1 accordingto an example embodiment may be grouped into subpixel groups. Forexample, one subpixel group may include four unit pixels PX.

The image sensor 1 according to an example embodiment may include aplurality of subpixel groups, each of which includes a plurality of unitpixels PX. Referring to FIG. 2, one of the plurality of unit pixels PX,pixel circuit PXC, of one of the plurality of subpixel groups mayinclude photodiodes PD1, PD2, PD3, and PD4 and a plurality ofsemiconductor devices for processing electrical charges generated by thephotodiodes PD1, PD2, PD3, and PD4. Each of the pixels of each of thesubpixel groups may include similar components.

For example, the pixel circuit PXC may include first to fourthphotodiodes PD1 to PD4, first to fourth transfer transistors TX1 to TX4,a reset transistor RX, a select transistor SX, and a driving transistorDX. The first to fourth photodiodes PD1 to PD4 included in the pixelcircuit PXC may share a floating diffusion region FD, a reset transistorRX, a select transistor SX, and a driving transistor DX. Gate electrodesof the first to fourth transfer transistors TX1 to TX4, the resettransistor RX, and the select transistor SX may be respectivelyconnected to the driving signal lines TG1 to TG4, RG, and SG. However,this is only an example, and example embodiments are not limited to thatillustrated in FIG. 2, and the pixel circuit PXC may be designed invarious manners.

In an example embodiment, any one pixel circuit PXC may generate a firstelectrical signal from the electrical charges generated by thephotodiodes PD1 to PD4 included in the corresponding pixel circuit PXCand output the first electric signal to the first column line, andanother pixel circuit may generate a second electrical signal from theelectrical charges generated by the photodiodes PD1 to PD4 included inthe corresponding pixel circuit and output the second electrical signalto the second column line. According to an example embodiment, two ormore pixel circuits disposed adjacent to each other may share one firstcolumn line. Similarly, two or more other pixel circuits disposedadjacent to each other may share one second column line. Pixel circuitsdisposed adjacent to each other may share some semiconductor devices.

The first to fourth transfer transistors TX1 to TX4 may be connected tothe first to fourth transfer gates TG1 to TG4 and the first to fourthphotodiodes PD1 to PD4, respectively. The first to fourth transfertransistors TX1 to TX4 may share the floating diffusion region FD. Thefirst to fourth photodiodes PD1 to PD4 may generate electrical chargesin proportion to the amount of externally incident light and accumulatethe electrical charges therein.

The first to fourth transfer transistors TX1 to TX4 may sequentiallytransfer electrical charges accumulated in the first to fourthphotodiodes PD1 to PD4 to the floating diffusion region FD. In order totransfer electrical charges generated by any one of the first to fourthphotodiodes PD1 to PD4 to the floating diffusion region FD, differentsignals may be applied to the first to fourth transfer gates TG1 to TG4.Accordingly, the floating diffusion region FD may accumulate electricalcharges generated by any one of the first to fourth photodiodes PD1 toPD4.

The reset transistor RX may periodically reset the electrical chargesaccumulated in the floating diffusion region FD. For example, electrodesof the reset transistor RX may be connected to the floating diffusionregion FD and a power supply voltage V_(DD). When the reset transistorRX is turned on, the electrical charges accumulated in the floatingdiffusion region FD may be discharged due to a potential difference withthe power supply voltage V_(DD) so the floating diffusion region FD maybe reset and a voltage of the floating diffusion region FD may be equalto the power supply voltage V_(DD).

An operation of the driving transistor DX may be controlled according tothe amount of electrical charges accumulated in the floating diffusionregion FD. The driving transistor DX may serve as a source-followerbuffer amplifier in combination with a current source disposed outsidethe unit pixel PX. For example, the driving transistor DX may amplify apotential change based on the electrical charges accumulated in thefloating diffusion region FD and output the amplified potential changeto an output line Vout.

The select transistor SX may select the unit pixels PX to be read in rowunits. When the select transistor SX is turned on, an electrical signaloutput from the driving transistor DX may be transmitted to the selecttransistor SX.

The image sensor 1 according to an example embodiment may provideautofocusing in at least one of the plurality of subpixel groupsincluding a plurality of unit pixels sharing the floating diffusionregion FD based on the pixel circuit PXC illustrated in FIG. 2. Forexample, the image sensor 1 may provide autofocusing in four directions(e.g., an up-down direction and a left-right direction) using the firstphotodiode PD1 to the fourth photodiode PD4.

As an example, the logic circuit may provide autofocusing in theleft-right direction using a first pixel signal acquired after the firsttransfer transistor TX1 is turned on and a second pixel signal acquiredafter the second transfer transistor TX2 is turned on. The logic circuitmay provide autofocusing in the up-down direction using the first pixelsignal acquired after the first transfer transistor TX1 is turned on anda third pixel signal acquired after the third transfer transistor TX3 isturned on. However, the pixel circuit of the unit pixel providing theautofocusing is not necessarily limited to the one illustrated in FIG.2, and some elements may be added or omitted as necessary.

FIGS. 3 and 4 are plan views illustrating pixel arrays included in animage sensor.

Referring to FIGS. 3 and 4, pixel arrays included in an image sensor mayinclude a plurality of unit pixels PX. For example, 2×2 arrays of theplurality of unit pixels PX may constitute subpixel groups SPG. 2×2arrays of the plurality of subpixel groups SPG may constitute pixelgroups PG. For example, a color filter of the same color may be providedon each of the unit pixels PX in a pixel group PG. In other words, thepixel arrays may include a plurality of pixel groups PG, each of whichcorresponds to a color filter, and each of the plurality of pixel groupsPG may include a plurality of unit pixels PX arranged in 4×4 form.

The color filters disposed on the plurality of pixel groups PG may haveany one of red (R), green (G), and blue (B) colors. For example, thepixel array of the image sensor may include color filters forming acolor filter array CFA repeatedly arranged in the order of green, red,blue, and green to correspond to a plurality of pixel groups PG arrangedin a 2×2 form.

In an image sensor, each of the plurality of unit pixels PX included inpixel arrays may include a photodiode. The plurality of unit pixels PXmay include a microlens on which light is incident in order to generatean electrical signal from the photodiode at the top thereof.

Referring to FIG. 3, in the pixel array of the image sensor, a microlensmay be disposed to correspond to each of the plurality of subpixelgroups SPG. For example, a plurality of unit pixels PX arranged in a 2×2form may share one microlens.

A plurality of unit pixels PX sharing one microlens may function as anautofocusing pixel. For example, the plurality of photodiodes includedin each of the plurality of unit pixels PX may be arranged in a seconddirection (e.g., an X-direction), perpendicular to a first direction(e.g., Z direction) in which the microlens is disposed, and in a thirddirection (e.g., Y-direction), perpendicular to the first direction andthe second direction. The image sensor may perform autofocusing in thesecond direction using a pixel signal acquired from two unit pixels PXarranged side by side in the second direction and may performautofocusing in the third direction using a pixel signal acquired fromtwo unit pixels PX arranged side by side in the third direction.Accordingly, the image sensor including the pixel array illustrated inFIG. 3 may perform autofocusing in four directions.

However, because the plurality of unit pixels PX included in onesubpixel group SPG share one microlens, light incident on one microlensmay be divided to be incident on four unit pixels PX. For example, lightthat passes through one microlens may be affected by reflection andrefraction. Accordingly, in the image sensor having the pixel arrayillustrated in FIG. 3, a remosaic process entailing a complicatedcorrection and a large amount of power consumption may be performed andan image having relatively low resolution may be generated, compared toan image sensor in which each of the plurality of unit pixels PXincludes a microlens.

Referring to FIG. 4, in the pixel array of the image sensor, a microlensmay be disposed to correspond to each of the plurality of unit pixelsPX. For example, one subpixel group SPG that includes unit pixels PXarranged in a 2×2 form may include microlenses that are also arranged ina 2×2 form.

The image sensor including the pixel array illustrated in FIG. 4 doesnot require a re-mosaic in an image generating process, and thus, animage having a relatively high resolution may be generated. However,light incident between the microlenses may be reflected and optical lossmay occur in connection with image generation of the image sensor. Inaddition, because the image sensor is configured such that thephotodiodes and the microlenses correspond to each other, there may be aproblem in that the autofocusing cannot be performed.

FIG. 5 is a plan view illustrating pixel groups included in an imagesensor according to an example embodiment.

FIG. 5 is a diagram illustrating pixel groups PG1 and PG2 correspondingto one color filter array included in the image sensor 100 andcomponents thereof according to an example embodiment. For example, onecolor filter array may include four pixel groups PG1 and PG2, and eachof the pixel groups PG1 and PG2 in the first direction (e.g., the Zdirection) may include a color filter having a predetermined color.

Referring to FIG. 5, in the image sensor 100 according to an exampleembodiment, each of the pixel groups PG1 and PG2 may include a pluralityof unit pixels PX arranged in 4×4 form. The pixel groups PG1 and PG2 mayinclude first pixel groups PG1 and second pixel groups PG2. The firstpixel groups PG1 and the second pixel groups PG2 may be alternatelyarranged with each other in the second direction (e.g., theX-direction), perpendicular to the first direction, and in the thirddirection (e.g., the Y-direction), perpendicular to the first directionand the second direction.

According to the example embodiment illustrated in FIG. 5, both of theplurality of first pixel groups PG1 may include a green color filter,one of the plurality of second pixel groups PG2 may include a red colorfilter, and another one of the plurality of second pixel groups PG2 mayinclude a blue color filter.

The plurality of unit pixels PX included in each of the pixel groups PG1and PG2 may be defined by a device isolation layer DTI disposedtherebetween, and each of the plurality of unit pixels PX isolated bythe device isolation layer DTI may include a photodiode PD. Each of thepixel groups PG1 and PG2 may include a microlens ML disposed on thecolor filter. The microlens ML may include a first microlens ML1 and asecond microlens ML2. The first microlens ML1 and the second microlensML2 may be disposed on top of the plurality of unit pixels PX in thefirst direction to allow external light to be incident thereon.

For example, the first pixel groups PG1 may include a first microlensML1 corresponding to each of the plurality of unit pixels PX (16 totalfirst microlenses ML1 in each first pixel group PG1), and the secondpixel group PG2 may include a second microlens ML2 shared by a pluralityof unit pixels PX arranged in a 2×2 form (four total microlenses ML2 ineach second pixel group PG2). For example, the first microlens ML1 mayhave a first diameter, and the second microlens ML2 may have a seconddiameter greater than the first diameter. In an example, the seconddiameter may be twice the first diameter. However, this is an exampleand example embodiments are not limited thereto. For example, as long asthe first microlens ML1 corresponds to the plurality of unit pixels PXand the second microlens ML2 corresponds to the subpixel group, thediameter and shape of the first microlens ML1 and the second microlensML2 may vary according to example embodiments.

Because the first microlens ML1 corresponds to one unit pixel PX, theplurality of unit pixels PX included in the first pixel group PG1 cannotoperate as an autofocusing pixel. However, an image generated using apixel signal acquired from the plurality of unit pixels PX included inthe first pixel group PG1 does not require a separate re-mosaic processand thus may have a relatively high resolution.

Because the second microlens ML2 corresponds to the unit pixels PXarranged in a 2×2 form, the plurality of unit pixels PX included in thesecond pixel group PG2 may act as an autofocusing pixel. For example, apixel signal acquired from a plurality of unit pixels PX sharing one ofthe second microlenses ML2 may include an autofocusing pixel signal. Theplurality of unit pixels PX included in the second pixel group PG2 mayperform an autofocusing in four directions, i.e., in the up-downdirection and the left-right direction. In addition, the image sensor100 may reduce optical loss using structural features of the secondmicrolens ML2 included in the second pixel group PG2.

The image sensor 100 according to an example embodiment uses both thefirst microlens ML1 and the second microlens ML2 having differentdiameters, thereby generating an image, to which the autofocusing isapplied and which has relatively high resolution, while calibrationrequired for generating an image and power consumption are reduced.

FIG. 6 is a plan view illustrating a first pixel group included in animage sensor according to an example embodiment.

Referring to FIG. 6, in the image sensor 100 according to an exampleembodiment, the first pixel group PG1 may include a plurality of unitpixels PX sharing the floating diffusion region FD and a plurality offirst subpixel groups SPG1 arranged in a 2×2 form. For example, each ofthe plurality of first subpixel groups SPG1 may include a plurality ofunit pixels PX arranged in a 2×2 form.

The first pixel group PG1 may include a color filter having apredetermined color. For example, the color filter included in the firstpixel group PG1 may be green. However, this is only an example, andexample embodiments are not limited thereto, and the color of the colorfilter may vary.

Each of the plurality of unit pixels PX may include a photodiode PDwhich generates an electrical signal by receiving external light. Theplurality of unit pixels PX may include first microlenses ML1corresponding the plurality of unit pixels PX, respectively. Forexample, the center of the first microlens ML1 may overlap thephotodiode PD in the first direction (e.g., the Z direction).

The plurality of unit pixels PX may be defined by a device isolationlayer DTI extending in the first direction. The device isolation layersDTI may be separated from each other in the second direction (e.g., theX-direction), perpendicular to the first direction in a region adjacentto the floating diffusion region FD and in the third direction (e.g.,the Y-direction), perpendicular to the first direction and the seconddirection. For example, the region between separated device isolationfilms DTI may be formed, one by one, in each of the first subpixelgroups SPG1.

The device isolation layer DTI may allow electrical charges generated inthe photodiodes PD respectively included in the plurality of unit pixelsPX to be accumulated in the corresponding photodiodes PD. In the imagesensor 100 according to an example embodiment, the device isolationlayer DTI defining the plurality of unit pixels PX included in the firstpixel group PG1 may be formed so that electrical charges generated bythe photodiodes PD included in the first pixel group GP1 do not overflowto the photodiodes PD included in other pixels.

In the first pixel group PG1 of the image sensor 100 according to anexample embodiment, the floating diffusion region FD included in thefirst subpixel group SPG1 may be shared between the plurality of unitpixels PX included in the first subpixel group SPG1. The deviceisolation layer DTI may be separated to an extent that overflow does notoccur between the plurality of unit pixels PX sharing the floatingdiffusion region FD.

FIGS. 7 to 9 are cross-sectional views illustrating a first pixel groupincluded in an image sensor according to an example embodiment.

FIGS. 7 to 9 are cross-sectional views of the image sensor 100illustrated in FIG. 6 taken along lines II-IF, III-III′ and IV-IV′,respectively. As an example, FIG. 7 is a cross-sectional viewillustrating a cross-section in the direction II-IF of FIG. 6, FIG. 8 isa cross-sectional view illustrating a cross-section taken along lineIII-III′ of FIG. 6, and FIG. 9 is a cross-sectional view illustrating across-section taken along line IV-IV′.

Referring to FIGS. 7 to 9, the image sensor 100 according to an exampleembodiment may include a substrate 110 including a first surface 111 anda second surface 112 facing each other, and a device isolation layer DTIdisposed between a plurality of unit pixels PX in the substrate 110. Forexample, the plurality of unit pixels PX may be arranged in a direction,parallel to the first surface 111 of the substrate 110. The plurality ofunit pixels PX may include photodiodes PD disposed inside the substrate110, respectively.

In the first pixel group PG1 included in the image sensor 100 accordingto an example embodiment, a color filter 120, a light transmitting layer130, and a first microlens ML1 may be sequentially disposed on the firstsurface 111 of the substrate 110 in the first pixel group PG1. Forexample, in the first pixel group PG1, the color filter 12 may be green,and the first microlens ML1 may correspond to each of the plurality ofunit pixels PX. However, this is an example and example embodiments arenot limited thereto.

Light that passes through the first microlens ML1 may be incident on aphotodiode included in an individual one of the plurality of unit pixelsPX. As described above, the first pixel group PG1 of the image sensor100 according to an example embodiment may improve resolution of agenerated image using the plurality of unit pixels PX sharing thefloating diffusion region FD and the first microlenses ML1 respectivelycorresponding to the plurality of unit pixels ML1.

In the image sensor 100 according to an example embodiment, a pixelcircuit may be disposed below the photodiode PD. For example, the pixelcircuit may include a plurality of elements 160, wiring patterns 170connected to the plurality of elements 160, and an insulating layer 180covering the plurality of elements 160 and the wiring patterns 170, andmay be disposed on the second surface 112 of the substrate 110. Thepixel circuit may operate to acquire a pixel signal from the pluralityof unit pixels PX.

The pixel circuit may include a floating diffusion region FD. Forexample, the plurality of unit pixels PX included in the first subpixelgroup may share the floating diffusion region FD disposed therebetween.However, the floating diffusion region FD is not limited to thoseillustrated in FIGS. 8 and 9. For example, a position and area of thefloating diffusion region FD may be modified to vary according toexample embodiments.

The plurality of elements 160 adjacent to the floating diffusion regionFD may be first to fourth transfer transistors. A gate of each of thefirst to fourth transfer transistors may have a vertical structure inwhich at least a partial region is embedded in the substrate 110.

As illustrated in FIG. 7, the plurality of unit pixels PX included inthe first pixel group PG1 of the image sensor 100 according to anexample embodiment may be separated from each other by the deviceisolation layer DTI. The device isolation layer DTI may be separatedfrom each other in the second and third directions as illustrated inFIGS. 8 and 9, and the floating diffusion region FD may be disposed inthe region between separated device isolation layers DTI. The deviceisolation layer DTI may be separated to such an extent that an overflowof electrical charges does not occur between adjacent photodiodes.

FIG. 10 is a plan view illustrating a second pixel group included in animage sensor according to an example embodiment.

Referring to FIG. 10, in the image sensor 100 according to an exampleembodiment, the second pixel group PG2 may include a plurality of secondsubpixel groups SPG2 including a plurality of unit pixels PX sharing thefloating diffusion region FD and arranged in a 2×2 form. For example,each of the plurality of second subpixel groups SPG2 may include aplurality of unit pixels PX arranged in a 2×2 form.

The second pixel group PG2 may include a color filter having apredetermined color. For example, the color filter included in thesecond pixel group PG2 may be red or blue. However, this is only anexample, and example embodiments are not limited thereto, and the colorof the color filter may vary.

Each of the plurality of unit pixels PX may include a photodiode PDwhich generates an electrical signal by receiving external light. Thesecond subpixel group SPG2 may include a second microlens ML2 shared bythe plurality of unit pixels PX included in the second subpixel groupPSG2. For example, the center of the second microlens ML2 may overlapthe floating diffusion region FD in the first direction (e.g., the Zdirection).

Because the second microlens ML2 is shared by the plurality of unitpixels PX arranged in a 2×2 form included in one second subpixel groupSPG2, the plurality of unit pixels PX included in the second pixel groupPG2 may include an autofocusing pixel. The plurality of unit pixels PXmay perform an autofocusing in the second direction (e.g., theX-direction), perpendicular to the first direction, and in the thirddirection (e.g., the Y-direction), perpendicular to the first and seconddirections. For example, the unit pixels PX arranged side by side in thesecond direction may perform an autofocusing using a phase difference inthe left and right directions of incident light, and the unit pixels PXarranged side by side in the third direction may perform theautofocusing using a phase difference in an up-down direction ofincident light.

Like the first pixel group PG1 illustrated in FIG. 6, the plurality ofunit pixels PX may be defined by the device isolation layer DTIextending in the first direction. The device isolation layer DTI may beseparated from each other in a region adjacent to the floating diffusionregion FD. For example, a region between separated device isolationlayers DTI may be formed in each of the second subpixel groups SPG2.However, a length of the region between the separated device isolationlayers DTI in the second direction and/or in the third direction in thesecond pixel group PG2, may be greater than a length of the regionbetween the separated device isolation layers DTI in the seconddirection and/or in the third direction in the first pixel group PG1.

The device isolation layer DTI may allow electrical charges generated inthe photodiodes PD respectively included in the plurality of unit pixelsPX to be accumulated in the corresponding photodiodes PD. In the imagesensor 100 according to an example embodiment, the device isolationlayer DTI defining the plurality of unit pixels PX included in thesecond pixel group PG2 may include an overflow region OF in whichgenerated electrical charges overflow to the photodiode PD included inan adjacent pixel when the photodiode PD included in each of theplurality of unit pixels is saturated.

According to an example embodiment, the floating diffusion region FDincluded in the second subpixel group SPG2 may be shared between theplurality of unit pixels PX included in the second subpixel group SPG2.The device isolation layer DTI may be separated between the plurality ofunit pixels PX sharing the floating diffusion region FD to form theoverflow region OF.

In the image sensor 100 according to an example embodiment, the overflowregion OF included in the second pixel group PG2 may prevent saturationof the photodiode PD due to electrical charges generated in excess ofcapacitance of each of the plurality of unit pixels PX. Therefore, amaximum amount of electrical charges that may be generated andaccumulated in each of the plurality of unit pixels PX included in thesecond pixel group PG2 may be greater than a maximum amount ofelectrical charges that may be generated and accumulated in each of theplurality of unit pixels PX included in the first pixel group PG1.

FIGS. 11, 12, and 13 are cross-sectional views illustrating a secondpixel group included in an image sensor according to an exampleembodiment.

FIGS. 11, 12, and 13 are cross-sectional views of the image sensor 100illustrated in FIG. 10 taken along lines V-V′, VI-VI′ and VII-VII′,respectively. As an example, FIG. 11 is a cross-sectional viewillustrating a cross-section taken along line V-V′ of FIG. 10, FIG. 12is a cross-sectional view taken along line VI-VI′ of FIG. 10, and FIG.13 is a cross-sectional view taken along line VII-VII′ of FIG. 10.

FIGS. 11, 12, and 13 may correspond to FIGS. 7 to 9, respectively. Forexample, the components of the image sensor 100 illustrated in FIGS. 11to 13 may correspond to the components of the image sensor 100illustrated in FIGS. 7 to 9. However, the second pixel group PG2illustrated in FIGS. 11 to 13 may be different from the first pixelgroup PG1 illustrated in FIGS. 7 to 9 in relation to the secondmicrolens ML2, a color of the color filter 120, a shape of the deviceisolation layer DTI, and the overflow region OF.

In the second pixel group PG2 included in the image sensor 100 accordingto an example embodiment, the color filter 120, the light transmittinglayer 130, and the second microlens ML2 may be sequentially disposed onthe first surface 111 of the substrate 110. For example, in the secondpixel group PG2, the color filter 120 may be red or blue, and the secondmicrolens ML2 may be shared by a plurality of unit pixels included inthe second subpixel group SPG2. However, this is an example and exampleembodiments are not limited thereto.

Light that passes through an individual one of the second microlensesML2 may be incident on the photodiodes of the plurality of unit pixelsPX included in the second subpixel group SPG2 corresponding to theindividual second microlens ML2. As described above, in the second pixelgroup PG2 of the image sensor 100 according to an example embodiment,optical loss during image generation may be reduced and autofocusing maybe performed in four directions using the plurality of unit pixels PXsharing the floating diffusion region FD and the second microlens ML2shared by the plurality of unit pixels PX.

As illustrated in FIG. 10, the plurality of unit pixels PX included inthe second pixel group PG2 of the image sensor 100 according to anexample embodiment may be separated from each other by the deviceisolation layer DTI. The device isolation layers DTI may be separatedfrom each other in the second and third directions as illustrated inFIGS. 12 and 13, and the floating diffusion region FD may be disposed inthe region between separated device isolation layers DTI. The overflowregion OF may be disposed in the region between the separated deviceisolation layers DTI, i.e., between the floating diffusion region FD andthe device isolation layer DTI. Through the overflow region OF, beforeany one photodiode PD is saturated, electrical charges generated in thecorresponding photodiode PD may move to an adjacent photodiode.

FIGS. 14A, 14B, 15A, 15B, 16A, 16B and 17 are diagrams illustrating aprocess of manufacturing an image sensor according to an exampleembodiment.

FIGS. 14A, 14B, 15A, 15B, 16A, 16B and 17 may be views illustrating aprocess of manufacturing the image sensor 100 according to an exampleembodiment illustrated in FIGS. 5 to 13. FIGS. 14A, 15A, 16A, and 17 arecross-sectional views taken along line I-I′ of FIG. 6, and FIGS. 14B,15B, and 16B are top views of the image sensor 100 according to theprocess.

Referring to FIGS. 14A and 14B, a process for manufacturing the imagesensor 100 according to an example embodiment may include forming atrench H extending in the first direction (e.g., the Z-direction) in thesubstrate 110 to separate pixel regions in which a plurality of unitpixels PX are to be formed before the device isolation layer is formed.

In the image sensor 100 according to an example embodiment, a mask layer115 may be formed on an upper surface of the substrate 110 before thetrench H is formed. For example, the mask layer 115 may be a layer forprotecting the substrate 110 so that the substrate 110 is not etchedother than a region in which the trench H is to be formed during anetching process for forming the trench H.

The trench H may be formed by an etching process performed after themask layer 115 is formed. However, a shape of the trench H illustratedin FIGS. 14A and 14B is not limited, and the shape of the trench H maybe modified to vary according to example embodiments.

The device isolation layer included in the image sensor 100 according toan example embodiment may be formed by a front deep trench isolation(FDTI) process. Accordingly, the trench H for forming the deviceisolation layer may be formed in a direction from the second surface ofthe substrate 110 on which the pixel circuit is to be disposed to thefirst surface of the substrate 110 on which the microlens is to bedisposed. However, this is an example, and example embodiments are notlimited thereto.

In the image sensor 100 according to an example embodiment, deviceisolation layers formed in the first pixel group may be different fromdevice isolation layers formed in the second pixel group. For example,the device isolation layers may be separated from each other in a regionin which a floating diffusion region is to be formed. Accordingly, thetrench H formed through an etching process to form the device isolationlayer may not completely penetrate through the substrate 110, and may beformed in the region in which the first pixel group is to be formed, andthe trench H formed in a region in which the first pixel group is to beformed may be different from the trench H formed in a region in whichthe second pixel group is to be formed in the second direction (e.g.,the X-direction) and the third direction (e.g., the Y-direction).

Referring to FIG. 14B, the trench H for forming the device isolationlayer included in the region in which the first pixel group is to beformed may be separated by a length of D1 in the second and thirddirections. The trench H for forming the device isolation layer includedin the region in which the second pixel group is to be formed may beseparated by a length D2 in the second and third directions. Forexample, D1 may be smaller than D2. The illustrated cross-section in theIT direction may pass through the trench H included in the region inwhich the first pixel group is to be formed and may not pass through thetrench H included in the region in which the second pixel group will beformed.

Referring to FIGS. 15A and 15B, the process for manufacturing the imagesensor 100 according to an example embodiment may include implantingimpurities into the substrate 110 through the trench H and forming adevice isolation layer DTI. For example, the impurities implanted intothe substrate 110 through the trench H may diffuse, and a photodiode PDmay be formed.

Because the depths of the trench H formed in the region in which thefirst pixel group is to be formed and in the region in which the secondpixel group is to be formed are different, a shape of the deviceisolation layer DTI formed in the trench H may also be changed. Forexample, in the region in which the second pixel group is to be formed,an overflow region OF to which electrical charges may move may be formedbetween the photodiodes PD.

Referring to FIGS. 16A and 16B, the process of manufacturing the imagesensor 100 according to an example embodiment may include forming thesecond surface 112 of the substrate 110 and disposing a pixel circuit onthe second surface 112. As described above, the pixel circuit mayinclude a plurality of elements 160, wiring patterns 170 connected tothe plurality of elements, and an insulating layer 180 covering theplurality of elements and the wiring patterns. For example, theplurality of elements may include a floating diffusion region FD.

After the device isolation layer DTI is formed, the mask layer 115 whichwas formed to perform the previous processes, a portion of the substrate110, and a portion of the device isolation layer DTI may be removed by apolishing process, etc. An upper surface of the substrate 110 removed bythe polishing process or the like may be the second surface 112. Forexample, a pixel circuit may be disposed on the second surface 112 ofthe substrate 110.

Referring to FIG. 17, a process of manufacturing the image sensor 100according to an example embodiment may include a process of removing apartial region of the substrate 110 from the opposite side of the pixelcircuit through a polishing process. For example, the region removed bythe polishing process may include a portion of the device isolationlayer DTI, and one surface of the substrate 110 remaining after theremoving may be the first surface 111.

The image sensor 100 according to an example embodiment may include thecolor filter 120, the light transmitting layer 130, and the first andsecond microlenses ML1 and ML2 sequentially disposed on the firstsurface 111 of the substrate 110. From this, the image sensor 100illustrated in FIGS. 5 and 17 may be manufactured. However, this is onlyan example, and a structure of the manufactured image sensor 100 is notlimited to that illustrated in FIG. 17.

FIGS. 18 to 20 are plan views illustrating pixel groups included in animage sensor according to another example embodiment.

FIG. 18 is a diagram illustrating pixel groups PG1 and PG2 correspondingto one color filter array included in an image sensor 200 and componentsthereof according to another example embodiment. For example, like theimage sensor 100 illustrated in FIG. 5, one color filter array maycorrespond to four pixel groups PG1 and PG2, and in the first direction(e.g., the Z direction), the pixel groups PG1 and PG2 may include acolor filter having a predetermined color in the first direction (e.g.,the Z direction).

Referring to FIG. 18, one color filter array may include green, red,blue, and green color filters arranged in the same order as illustratedin FIG. 5. Also, the plurality of pixel groups PG1 and PG2 may include aplurality of first pixel groups PG1 including first microlenses ML1respectively corresponding to the plurality of unit pixels PX and aplurality of second pixel groups PG2 including a second microlens ML2shared by a plurality of unit pixels PX arranged in a 2×2 form.

However, unlike the image sensor 100 illustrated in FIG. 5, in the imagesensor 200 illustrated in FIG. 18, a plurality of first pixel groups PG1may include a red or blue color filter, and the plurality of secondpixel groups PG2 may include a green color filter. As an example, anarrangement of components included in the image sensor 200 may be thesame as that of the image sensor 100 illustrated in FIG. 5.

FIGS. 19 and 20 may be diagrams illustrating the second pixel group PG2and the first pixel group PG1 of the image sensor 200 according to anexample embodiment, respectively. As an example, FIGS. 19 and 20 maycorrespond to FIGS. 10 and 6, respectively. However, in the image sensor200 illustrated in FIGS. 19 and 20, a color of a color filter may bedifferent from the image sensor 100 illustrated in FIGS. 10 and 6.

A person may recognize brightness, intensity, and color of lightentering the eye. In general, when green light is incident on the eye, aperson may most sensitively recognize brightness, intensity, and color.Accordingly, the image sensor 100 illustrating in FIG. 5 allowing animage having high resolution in the unit pixels PX corresponding to agreen color filter to be generated and performing autofocusing in theunit pixels PX corresponding to the red and blue color filter maycorrespond to an example embodiment closer to the human eye. However,this is only an example, and example embodiments are not limitedthereto, and an image may be generated using the image sensor 200illustrated in FIG. 18.

FIGS. 21 to 24 are plan views illustrating pixel arrays included in animage sensor according to example embodiments.

FIGS. 21 to 24 may be views illustrating a pixel array included in animage sensor according to other example embodiments together with theimage sensors 100 and 200 illustrated in FIGS. 5 and 18.

In the pixel arrays 100A, 200A, 300A, and 400A included in the imagesensor according to an example embodiment, the plurality of unit pixelsPX may configure subpixel groups SPG1 and SPG2 in every 2×2 array. Theplurality of subpixel groups SPG1 and SGP2 arranged in the 2×2 form mayconfigure pixel groups PG1 and PG2.

A color filter included in the plurality of pixel groups PG1 and PG2 mayhave any one of red (R), green (G), and blue (B) colors. As an example,the pixel arrays 100A, 200A, 300A, and 400A of the image sensor mayinclude color filters having a color filter array CFA repeatedlyarranged in an order of green, red, blue, and green to correspond to theplurality of pixel groups PG1 and PG2 arranged in the 2×2 form. However,this is only an example embodiment, and the repeatedly configured colorfilter arrangement CFA may vary. For example, a white color filter maybe included in the color filter array CFA.

In other words, in the pixel arrays 100A, 200A, 300A, and 400A, a colorfilter of the same color may be disposed for each pixel group PG1 andPG2, and each of the plurality of pixel groups PG1 and PG2 may include aplurality of unit pixels PX arranged in 4×4 form.

The plurality of pixel groups PG1 and PG2 may be divided into a firstpixel group PG1 or a second pixel group PG2. The first pixel group PG1may include the first subpixel group SPG1 and may include a firstmicrolens ML1 disposed on the substrate. The second pixel group PG2 mayinclude a second subpixel group SPG2 and may include a second microlensML2 disposed on the substrate. For example, each of the plurality ofpixel groups PG1 and PG2 may include only any one of the first subpixelgroup SPG1 or the second subpixel group SPG2.

For example, the pixel array 100A illustrated in FIG. 21 may be a pixelarray 100A included in the image sensor 100 illustrated in FIG. 5, andthe pixel array 200A illustrated in FIG. 22 may be a pixel array 200Aincluded in the image sensor 200 illustrated in FIG. 18.

Referring to the pixel array 300A according to an example embodimentillustrated in FIG. 23, the first pixel groups PG1 a and PG1 b mayinclude a color filter having any one of green, red, and blue colors.

For example, the second pixel group PG2 may include a red or blue colorfilter. At least one first pixel group PG1 a may include a green colorfilter. However, at least the other first pixel group PG1 b may includea red or blue color filter.

As described above, the first pixel groups PG1 a and PG1 b may includefirst subpixel groups SPG1 a and SPG1 b and may include a firstmicrolens ML1 disposed on the substrate. The second pixel group PG2 mayinclude a second subpixel group SPG2 and may include a second microlensML2 disposed on the substrate. Accordingly, the image sensor includingthe pixel array 300A according to an example embodiment may generate animage having high resolution but autofocusing performance may bereduced, when compared to the image sensor 100 illustrated in FIG. 5.

Referring to the pixel array 400A according to the example embodimentillustrated in FIG. 24, the second pixel groups PG2 a and PG2 b mayinclude a color filter having any one of green, red, and blue colors.

For example, the first pixel group PG1 may include a green color filter.At least one second pixel group PG2 a may include a red or blue colorfilter. However, at least another second pixel group PG2 b may include agreen color filter.

As described above, the first pixel groups PG1 a and PG1 b may includethe first subpixel groups SPG1 a and SPG1 b and may include the firstmicrolens ML1 disposed on the substrate. The second pixel group PG2 mayinclude a second subpixel group SPG2 and may include a second microlensML2 disposed on the substrate. Accordingly, in the image sensorincluding the pixel array 400A according to an example embodiment,autofocusing performance may be improved, but resolution of thegenerated image may be reduced when compared to the image sensor 100illustrated in FIG. 5.

However, the shape of the pixel array included in the image sensoraccording to an example embodiment is not limited to those illustratedin FIGS. 21 to 24. As an example, the image sensor include first pixelgroups PG1 and second pixel groups PG2 that are variously arranged togenerate an image having appropriate resolution with appropriateautofocusing performance as necessary.

FIGS. 25 and 26 are diagrams illustrating an electronic device includingan image sensor according to an example embodiment.

Referring to FIG. 25, an electronic device 1000 may include a cameramodule group 1100, an application processor 1200, a power managementintegrated circuit (PMIC) 1300, and an external memory 1400.

The camera module group 1100 may include a plurality of camera modules1100 a, 1100 b, and 1100 c. Although three camera modules 1100 a, 1100b, and 1100 c are disposed in the drawing, example embodiments are notlimited thereto. In some example embodiments, the camera module group1100 may be modified to include only two camera modules or only onecamera module. Also, in some example embodiments, the camera modulegroup 1100 may be modified to include n (n is a natural number of 4 orgreater) camera modules. Also, in an example embodiment, at least one ofthe plurality of camera modules 1100 a, 1100 b, and 1100 c included inthe camera module group 1100 may include an image sensor according toone of the example embodiments described above with reference to FIGS. 1to 24.

Hereinafter, a detailed configuration of the camera module 1100 b willbe described in more detail with reference to FIG. 26, and the followingdescription will be equally applied to other camera modules 1100 a and1100 b according to an example embodiment.

As illustrated in FIG. 26, the camera module 1100 b may include a prism1105, an optical path folding element (OPFE) 1110, an actuator 1130, animage sensing device 1140, and a storage 1150.

The prism 1105 may include a reflective surface 1107 of a lightreflective material to modify a path of light L from the outside that isincident on the reflective surface 1107.

In some example embodiments, the prism 1105 may change a path of thelight L incident in the second direction X to the third direction Y,perpendicular to the second direction X. In addition, the prism 1105 mayrotate the reflective surface 1107 of the light reflective materialabout the central axis 1106 in an A direction or in a B direction tochange a path of the light L incident in the second direction X into thevertical third direction Y. At this time, the OPFE 1110 may also move inthe first direction Z, perpendicular to the second direction X and thethird direction Y.

In some example embodiments, as shown, a maximum rotation angle of theprism 1105 in the A direction may be 15 degrees or less in a positive(+) A direction and may be greater than 15 degrees in a negative (−) Adirection, but example embodiments are not limited thereto.

In some example embodiments, the prism 1105 may be movable at about 20degrees, between 10 degrees and 20 degrees, or between 15 degrees and 20degrees in a positive (+) or negative (−) B direction, and here, in themoving angle, the prism 1105 may move at the same angle in the positive(+) or negative (−) B direction or move to a nearly similar angle withina range of 1 degree.

In some example embodiments, the prism 1105 may move on the reflectivesurface 1107 of the light reflective material in the first direction(e.g., the Z direction), parallel to an extending direction of thecentral axis 1106.

The OPFE 1110 may include, for example, an optical lens including m(where m is a natural number) groups. The m lenses may move in the thirddirection Y to change an optical zoom ratio of the camera module 1100 b.For example, when a basic optical zoom ratio of the camera module 1100 bis Z, if m optical lenses included in the OPFE 1110 are moved, theoptical zoom ratio of the camera module 1100 b may be changed to 3Z or5Z or higher than 5Z.

The actuator 1130 may move the OPFE 1110 or an optical lens (hereinafterreferred to as an optical lens) to a specific position. For example, theactuator 1130 may adjust a position of the optical lens so that theimage sensor 1142 is positioned at a focal length of the optical lensfor accurate sensing.

The image sensing device 1140 may include an image sensor 1142, acontrol logic 1144, and a memory 1146. The image sensor 1142 may sensean image of a sensing target using light L provided through the opticallens. The control logic 1144 may control an overall operation of thecamera module 1100 b. For example, the control logic 1144 may controlthe operation of the camera module 1100 b according to a control signalprovided through a control signal line CSLb.

The memory 1146 may store information necessary for the operation of thecamera module 1100 b, such as calibration data 1147. The calibrationdata 1147 may include information necessary for the camera module 1100 bto generate image data using the light L provided from the outside. Thecalibration data 1147 may include, for example, information on a degreeof rotation, information on a focal length, and information on anoptical axis, as described above. When the camera module 1100 b isimplemented as a multi-state camera in which the focal length is changedaccording to a position of the optical lens, the calibration data 1147may include a focal length value of the optical lens for each position(or state) and information related to autofocusing.

The storage 1150 may store the image data sensed through the imagesensor 1142. The storage 1150 may be disposed outside the image sensingdevice 1140 and may be implemented in a stacked form with a sensor chipconstituting the image sensing device 1140. In some example embodiments,the storage 1150 may be implemented as an electrically erasableprogrammable read-only memory (EEPROM), but example embodiments are notlimited thereto.

Referring to FIGS. 25 and 26 together, in some example embodiments, eachof the plurality of camera modules 1100 a, 1100 b, and 1100 c mayinclude an actuator 1130. Accordingly, each of the plurality of cameramodules 1100 a, 1100 b, and 1100 c may include the same or differentcalibration data 1147 according to an operation of the actuator 1130included therein.

In some example embodiments, one camera module (e.g., 1100 b) among theplurality of camera modules 1100 a, 1100 b, and 1100 c may be a foldedlens type camera module including the prism 1105 and the OPFE 1110described above and the other camera modules (e.g., 1100 a and 1100 c)may be vertical type camera modules without the prism 1105 and the OPFE1110, but example embodiment are not limited thereto.

In some example embodiments, one camera module (e.g., 1100 c) among theplurality of camera modules 1100 a, 1100 b, and 1100 c may be a verticaltype depth camera which extracts depth information using infrared (IR)rays. In this case, the application processor 1200 may generate a 3Ddepth image by merging image data provided from such a depth camera withimage data provided from another camera module (e.g., 1100 a or 1100 b).

In some example embodiments, at least two camera modules (e.g., 1100 aand 1100 b) among the plurality of camera modules 1100 a, 1100 b, and1100 c may have different fields of view. In this case, for example,optical lenses of at least two camera modules (e.g., 1100 a and 1100 b)among the plurality of camera modules 1100 a, 1100 b, and 1100 c may bedifferent from each other, but example embodiments are not limitedthereto.

Also, in some example embodiments, viewing angles of the plurality ofcamera modules 1100 a, 1100 b, and 1100 c may be different from eachother. In this case, the optical lenses included in each of theplurality of camera modules 1100 a, 1100 b, and 1100 c may also bedifferent, but example embodiments are not limited thereto.

In some example embodiments, each of the plurality of camera modules1100 a, 1100 b, and 1100 c may be disposed to be physically separatedfrom each other. That is, instead of dividing the sensing area of oneimage sensor 1142 into areas for each of the plurality of camera modules1100 a, 1100 b, and 1100 c, an independent image sensor 1142 may bedisposed inside each of the plurality of camera modules 1100 a, 1100 b,and 1100 c.

Referring back to FIG. 25, the application processor 1200 may include animage processing device 1210, a memory controller 1220, and an internalmemory 1230. The application processor 1200 may be implementedseparately from the plurality of camera modules 1100 a, 1100 b, and 1100c. For example, the application processor 1200 and the plurality ofcamera modules 1100 a, 1100 b, and 1100 c may be implemented separatelyas separate semiconductor chips.

The image processing device 1210 may include a plurality of sub-imageprocessors 1212 a, 1212 b, and 1212 c, an image generator 1214, and acamera module controller 1216.

The image processing device 1210 may include a plurality of sub-imageprocessors 1212 a, 1212 b, and 1212 c in a number corresponding to thenumber of the plurality of camera modules 1100 a, 1100 b, and 1100 c.

Image data generated by each of the camera modules 1100 a, 1100 b, and1100 c may be provided to the corresponding sub-image processors 1212 a,1212 b, and 1212 c through image signal lines ISLa, ISLb, and ISLcseparated from each other. For example, image data generated by thecamera module 1100 a may be provided to the sub-image processor 1212 athrough the image signal line ISLa, image data generated by the cameramodule 1100 b may be provided to the sub-image processor 1212 b throughthe image signal line ISLb, and image data generated by the cameramodule 1100 c may be provided to the sub-image processor 1212 c throughthe image signal line ISLc. Such image data transmission may beperformed using, for example, a camera serial interface (CSI) based on amobile industry processor interface (MIPI), but example embodiments arenot limited thereto.

In some example embodiments, one sub-image processor may be disposed tocorrespond to a plurality of camera modules. For example, the sub-imageprocessor 1212 a and the sub-image processor 1212 c are not implementedseparately from each other as shown but may be integrated into onesub-image processor, and image data provided from the camera module 1100a and the camera module 1100 c may be selected through a selectingelement (e.g., a multiplexer) and provided to the integrated sub-imageprocessor.

The image data provided to each sub-image processor 1212 a, 1212 b, and1212 c may be provided to the image generator 1214. The image generator1214 may generate an output image using the image data provided fromeach of the sub-image processors 1212 a, 1212 b, and 1212 c according toimage generating information or a mode signal.

Specifically, the image generator 1214 may generate an output image bymerging at least some of image data generated by the camera modules 1100a, 1100 b, and 1100 c having different viewing angles according to theimage generating information or the mode signal. In addition, the imagegenerator 1214 may generate an output image by selecting any one ofimage data generated by the camera modules 1100 a, 1100 b, and 1100 chaving different viewing angles according to image generatinginformation or the mode signal.

In some example embodiments, the image generating information mayinclude a zoom signal or zoom factor. Also, in some example embodiments,the mode signal may be, for example, a signal based on a mode selectedby a user.

When the image generating information is a zoom signal (zoom factor) andeach of the camera modules 1100 a, 1100 b, and 1100 c has differentviewing fields (viewing angles), the image generator 1214 may performdifferent operations according to types of the zoom signals. Forexample, when the zoom signal is a first signal, the image generator1214 may merge image data output from the camera module 1100 a and imagedata output from the camera module 1100 c and then generate an outputimage using image data output from the camera module 1100 b which hasnot been used for merging with the merged image signal. If the zoomsignal is a second signal different from the first signal, the imagegenerator 1214 may not perform such image data merging and may selectany one of the image data output from each of the camera modules 1100 a,1100 b, and 1100 c to generate an output image. However, exampleembodiments are not limited thereto, and the method of processing imagedata may be modified and implemented as needed.

In some example embodiments, the image generator 1214 may receive aplurality of image data with different exposure times from at least oneof the plurality of sub-image processors 1212 a, 1212 b, and 1212 c andperform high dynamic range (HDR) processing to generate merged imagedata having an increased dynamic range.

The camera module controller 1216 may provide a control signal to eachof the camera modules 1100 a, 1100 b, and 1100 c. The control signalgenerated by the camera module controller 1216 may be provided to thecorresponding camera modules 1100 a, 1100 b, and 1100 c through thecontrol signal lines CSLa, CSLb, and CSLc separated from each other.

Any one of the plurality of camera modules 1100 a, 1100 b, and 1100 cmay be designated as a master camera (e.g., 1100 b) according to imagegenerating information including a zoom signal or a mode signal, and theother camera modules (e.g., 1100 a and 1100 c) may be designated asslave cameras. Such information may be included in the control signaland provided to the corresponding camera modules 1100 a, 1100 b, and1100 c through the control signal lines CSLa, CSLb, and CSLc separatedfrom each other.

The camera module operating as a master and a slave may be changedaccording to a zoom factor or an operation mode signal. For example,when a viewing angle of the camera module 1100 a is wider than a viewingangle of the camera module 1100 b and a zoom factor indicates a low zoommagnification, the camera module 1100 b may operate as a master and thecamera module 1100 a may operate as a slave. Conversely, when the zoomfactor indicates a high zoom magnification, the camera module 1100 a mayoperate as a master and the camera module 1100 b may operate as a slave.

In some example embodiments, the control signal provided to each of thecamera modules 1100 a, 1100 b, and 1100 c from the camera modulecontroller 1216 may include a sync enable signal. For example, when thecamera module 1100 b is a master camera and the camera modules 1100 aand 1100 c are slave cameras, the camera module controller 1216 maytransmit a sync enable signal to the camera module 1100 b. The cameramodule 1100 b receiving the sync enable signal may generate a syncsignal based on the received sync enable signal and transmit thegenerated sync signal to the camera modules 1100 a and 1100 c. Thecamera module 1100 b and the camera modules 1100 a and 1100 c may besynchronized with the sync signal to transmit image data to theapplication processor 1200.

In some example embodiments, the control signal provided from the cameramodule controller 1216 to the plurality of camera modules 1100 a, 1100b, and 1100 c may include mode information according to a mode signal.Based on the mode information, the plurality of camera modules 1100 a,1100 b, and 1100 c may operate in a first operation mode and a secondoperation mode in relation to a sensing rate.

The plurality of camera modules 1100 a, 1100 b, and 1100 c may generatean image signal at a first rate (e.g., generate an image signal at afirst frame rate) in the first operation mode, encode the generatedimage signal at a second rate higher than the first rate (e.g., encodethe image signal at a second frame rate higher than the first framerate), and transmit the encoded image signal to the applicationprocessor 1200. In this case, the second rate may be 30 times or less ofthe first rate.

The application processor 1200 may store the transmitted image signal,i.e., the encoded image signal, in the internal memory 1230 providedtherein or an external memory 1400 outside the application processor1200, and thereafter, the application processor 1200 may read theencoded image signal from the memory 1230 or the external memory 1400,decode the read image signal, and display image data generated based onthe decoded image signal. For example, a corresponding sub-processoramong the plurality of sub-image processors 1212 a, 1212 b, and 1212 cof the image processing device 1210 may perform decoding and may alsoperform image processing on the decoded image signal.

The plurality of camera modules 1100 a, 1100 b, and 1100 c may generatean image signal at a third rate lower than the first rate in the secondoperation mode (e.g., generate the image signal at a third frame ratelower than the first frame rate) and transmit the image signal to theapplication processor 1200. The image signal provided to the applicationprocessor 1200. The image signal provided to the application processor1200 may be a signal which has not been encoded. The applicationprocessor 1200 may perform image processing on the received image signalor store the image signal in the memory 1230 or the external memory1400.

The PMIC 1300 may supply power, e.g., a power supply voltage, to each ofthe plurality of camera modules 1100 a, 1100 b, and 1100 c. For example,the PMIC 1300 may supply first power to the camera module 1100 a throughthe power signal line PSLa, supply second power to the camera module1100 b through the power signal line PSLb, and supply third power to thecamera module 1100 c through the power signal line PSLc under thecontrol of the application processor 1200.

In response to a power control signal PCON from the applicationprocessor 1200, the PMIC 1300 generates power corresponding to each ofthe plurality of camera modules 1100 a, 1100 b, and 1100 c, and adjust alevel of power. The power control signal PCON may include a poweradjustment signal for each operation mode of the plurality of cameramodules 1100 a, 1100 b, and 1100 c. For example, the operation mode mayinclude a low power mode, and in this case, the power control signalPCON may include information on a camera module operating in the lowpower mode and a set power level. The levels of power provided to eachof the plurality of camera modules 1100 a, 1100 b, and 1100 c may be thesame or different from each other. Also, the levels of power may bechanged dynamically.

As set forth above, the image sensor according to an example embodimentsecures autofocusing in four directions using a first microlenscorresponding to each of a plurality of photodiodes and a secondmicrolens shared by the plurality of photodiodes, and may generate animage having a higher image quality than that of the related art imagesensor.

The image sensor according to an example embodiment may include anoverflow region for moving excessively generated electrical charges,thereby preventing saturation of the photodiodes due to the electricalcharges generated in the photodiodes.

While example embodiments have been shown and described above, it willbe apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of theappended claims.

What is claimed is:
 1. An image sensor comprising: a substrate having afirst surface and a second surface which faces the first surface; apixel array comprising a plurality of first pixel groups and a pluralityof second pixel groups, each of the plurality of first pixel groups andeach of the plurality of second pixel groups comprising a plurality ofunit pixels arranged in 4×4 array that extends in a second direction andin a third direction, each of the plurality of unit pixels comprising aphotodiode provided in the substrate, and the plurality of first pixelgroups and the plurality of second pixel groups being alternatelydisposed in the second direction and in the third direction; a logiccircuit configured to acquire pixel signals from the plurality of unitpixels; a plurality of first microlenses, each of which is provided on acorresponding unit pixel of the plurality of unit pixels included in theplurality of first pixel groups; and a plurality of second microlenses,each of which is respectively provided on four corresponding unit pixelsof the plurality of unit pixels included in the plurality of secondpixel groups that are arranged in a 2×2 array, wherein a first directionis perpendicular to the first surface of the substrate, the seconddirection is parallel to the first surface of the substrate, and thethird direction is parallel to the first surface of the substrate andperpendicular to the second direction, each of the plurality of firstpixel groups and each of the plurality of second pixel groups comprisesa device isolation layer provided between the plurality of unit pixels,and a color filter provided on the first surface, and each of theplurality of second pixel groups comprises an overflow region configuredto move electrical charges between adjacent photodiodes.
 2. The imagesensor of claim 1, wherein a center of a second microlens of theplurality of second microlenses overlaps a floating diffusion region inthe first direction.
 3. The image sensor of claim 1, wherein a center ofa first microlens of the plurality of first microlenses overlaps thephotodiode below the first microlens in the first direction.
 4. Theimage sensor of claim 1, wherein the color filter corresponding to eachof the plurality of unit pixels in each pixel group of the plurality offirst pixel groups and the plurality of second pixel groups share acommon color.
 5. The image sensor of claim 4, wherein the color filtercorresponding to each of the plurality of unit pixels in the pluralityof first pixel groups is green, and the color filter corresponding toeach of the plurality of unit pixels in the plurality of second pixelgroups is red or blue.
 6. The image sensor of claim 4, wherein the colorfilter corresponding to each of the plurality of unit pixels in theplurality of first pixel groups is red or blue, and the color filtercorresponding to each of the plurality of unit pixels in the pluralityof second pixel groups is green.
 7. The image sensor of claim 1, whereinthe plurality of unit pixels share a floating diffusion region at every2×2 array.
 8. The image sensor of claim 1, wherein the plurality of unitpixels included in the plurality of second pixel groups comprise anautofocusing pixel.
 9. The image sensor of claim 8, wherein the logiccircuit is configured to perform autofocusing based on the pixel signalsacquired from the autofocusing pixel with respect to the seconddirection and the third direction.
 10. The image sensor of claim 1,wherein each of the plurality of unit pixels in the plurality of secondpixel groups is configured to accumulate a greater amount of electricalcharges than a maximum amount of electrical charges that may beaccumulated in each of the plurality of unit pixels in the plurality offirst pixel groups.
 11. An image sensor comprising: a substrate having afirst surface and a second surface which faces the first surface; apixel array comprising a plurality of subpixel groups comprising aplurality of first subpixel groups and a plurality of second subpixelgroups, each of the plurality of first subpixel groups and each of theplurality of second subpixel groups comprising a plurality of unitpixels arranged in a 2×2 array that extends in a second direction and ina third direction, and a floating diffusion region that is shared by theplurality of unit pixels arranged in the 2×2 array, and each of theplurality of unit pixels comprising a photodiode provided in thesubstrate; a logic circuit configured to acquire pixel signals from theplurality of unit pixels; a plurality of first microlenses, each ofwhich is provided on a corresponding unit pixel of the plurality of unitpixels included in the plurality of first subpixel groups; and aplurality of second microlenses, each of which is respectively providedon a plurality of corresponding unit pixels of the plurality of secondsubpixel groups, wherein a first direction is perpendicular to the firstsurface of the substrate, the second direction is parallel to the firstsurface of the substrate, and the third direction is parallel to thefirst surface of the substrate and perpendicular to the seconddirection, each of the plurality of subpixel groups is adjacent to oneof the plurality of first subpixel groups and one of the plurality ofsecond subpixel groups in each of the second direction and the thirddirection, and comprises a device isolation layer provided between theplurality of unit pixels and separated from the floating diffusionregion in the second direction and in the third direction, and adjacentportions of the device isolation layer extending in the second directionin the plurality of first subpixel groups are closer to each other thanadjacent portions of the device isolation layer extending in the seconddirection in the plurality of second subpixel groups.
 12. The imagesensor of claim 11, wherein each of the plurality of second subpixelgroups comprises an overflow region configured to move electricalcharges between adjacent photodiodes.
 13. The image sensor of claim 12,wherein the overflow region is provided between the floating diffusionregion and the device isolation layer.
 14. The image sensor of claim 11,wherein a green color filter is provided on an upper surface of theplurality of unit pixels of each of the plurality of first subpixelgroups.
 15. The image sensor of claim 14, wherein a red or blue colorfilter is provided on an upper surface of the plurality of unit pixelsof at least one of the plurality of second subpixel groups.
 16. Theimage sensor of claim 11, wherein a red or blue color filter is providedon an upper surface of the plurality of unit pixels of each of theplurality of second subpixel groups.
 17. The image sensor of claim 16,wherein a green color filter is provided on an upper surface of theplurality of unit pixels of at least one of the plurality of firstsubpixel groups.
 18. An image sensor comprising: a substrate having afirst surface and a second surface which faces the first surface; apixel array comprising a plurality of first pixel groups and a pluralityof second pixel groups, each of the plurality of first pixel groups andthe plurality of second pixel groups comprising a plurality of unitpixels defined by a device isolation layer extending through thesubstrate in a first direction, the plurality of unit pixels in each ofthe plurality of first pixel groups and the plurality of second pixelgroups being arranged in 4×4 array that extends in a second directionand in a third direction, each of the plurality of unit pixelscomprising a photodiode provided inside the substrate, and the pluralityof first pixel groups and the plurality of second pixel groups beingalternately disposed in the second direction and in the third direction;a logic circuit configured to acquire pixel signals from the pluralityof unit pixels; a plurality of first microlenses having a first diameterand respectively corresponding to the plurality of unit pixels aredisposed on an upper surface of the plurality of first pixel groups; anda plurality of second microlenses having a second diameter greater thanthe first diameter are disposed on an upper surface of the plurality ofsecond pixel groups, wherein the first direction is perpendicular to thefirst surface of the substrate, the second direction is parallel to thefirst surface of the substrate, and the third direction is parallel tothe first surface of the substrate and perpendicular to the seconddirection, and a pixel signal acquired from unit pixels of the pluralityof unit pixels sharing one of the plurality of second microlensescomprises an autofocusing pixel signal with respect to the seconddirection and the third direction.
 19. The image sensor of claim 18,wherein each of the plurality of second pixel groups comprises anoverflow region configured to move electrical charges between adjacentphotodiodes.
 20. The image sensor of claim 18, wherein each of theplurality of first pixel groups and the plurality of second pixel groupscomprises a plurality of floating diffusion regions, the deviceisolation layer is separated from each of the plurality of floatingdiffusion regions, and adjacent portions of the device isolation layerextending in the second direction in the plurality of first pixel groupsare closer to each other than adjacent portions of the device isolationlayer extending in the second direction in the plurality of second pixelgroups.